Field of the Invention
The present invention relates to a poly(carbon monofluoride) cathode for use in electrochemical cells, particularly as a cathode in electrochemical cells having a light metal anode.
Electrochemical cells, such as those disclosed in U.S. Pat. No. 3,700,502 and U.S. Pat. No. 3,536,532 are used in many portable devices requiring electrical power. Such devices include cameras that use motors for film advance and electronic flash units for supplemental light.
Commercial embodiments of the electrochemical cells disclosed in the aforementioned U.S. patents comprise a lithium anode and a cathode structure comprising a dispersion of poly(carbon monofluoride) hereinafter referred to as (CF.sub.x).sub.n wherein n is an indeterminately large number, carbon and a non-adhesive binder [poly(tetrafluoroethylene) also known as Teflon.RTM.] molded to a titanium grid. The electrolyte is 1M LiBF.sub.4 in .gamma.-butyrolactone. These electrochemical cells usually have a limiting current density of about 50-60 milliamperes per square centimeter (mA/cm.sup.2) and maximum power density of about 29-35 milliwatts per square centimeter (mW/cm.sup.2). The problem associated with the latter cells is that, although they are useful in many applications, greater limiting current densities and maximum power densities are needed for certain high power applications such as more rapidly charging electronic flashes in cameras, turning motors in cameras or tape recorders, setting off emergency alarms or providing emergency lighting.